Are you tried latest build from laboratory?anyway, I also hadn't that crash while I tested your level on both Windows and Linux platforms, so, that cloud be happened because you had old build (carefully compare revision numbers every download if version number is same!) which had that bug.EDIT: that "same" copy of level because you had an automatically saved editing states to avoid lose of them and then reloaded back, so, you almost never lose your progress if in some wired case crash will happen You cloud remove them from "__crashsaves" folder which you can also find in the %UserProfiles%\.PGE_Project folder if you not find it in PGE folder (dependent to way how you got PGE package: zip-file or online installer)